M/V Tiglax Sails for Science

Authors: Lisa Spitler and Jeff Williams | Alaska Maritime National Wildlife Refuge

Tiglax SketchThe M/V Tiglax (TEKH-lah – Aleut for eagle) is essential to managing the Alaska Maritime National Wildlife Refuge. The boat is 120 feet long and operates with a crew of 6. Fourteen scientists can live and work aboard. She has wet and dry labs and freezers for storing samples. Tiglax can deploy midwater and bottom trawls for sampling fish and plankton, and hosts bioacoustic transducers and data processors for sampling fish/plankton densities; and a SBE-21 thermosalinograph for diving seabird studies.

In a season, the Tiglax may sail to Forrester and St. Lazaria Islands in Southeast Alaska, or into Bering Sea as far as St. Matthew Island. Her main operations area is, however, the Aleutian Chain. Tiglax typically spends 120-160 days at sea covering as many as 20,000 nautical miles (at a top speed of 10 knots) traveling from the home port of Homer, Alaska out to Attu Island at the extreme west end of the Aleutian chain and back, several times a season.

The main role of the Tiglax is to transport service personnel, equipment, and supplies between work sites throughout the refuge. This year Tiglax departs Homer on May 17 to deploy FWS biologists and biological technicians at field camps in the Semidi Islands, on Aiktak, Buldir, Kiska, and Attu. These scientists focus on studying seabird colonies, but also work on reestablishing endangered habitats, they identify and monitor archaeological and historic sites, they monitor bird populations and human impacts on habitats, they maintain remote field facilities, and they patrol refuge waters.

 Tiglax also serves as a seagoing research platform and living quarters for scientists from the Fish and Wildlife Service (FWS) or other federal or state agencies and universities. This year’s FWS projects include removal of invasive foxes from islands to restore native bird populations, collecting background information on contaminants left over from World War II, and monitoring other contaminant cleanup efforts on Attu and Amchitka, studying Kasatochi Island as she recovers from an eruption in 2008, lichen research on Adak, and visiting remote bird nesting colonies.

Non FWS partners include the National Marine Fisheries Service for sea lion studies, the University of Alaska, Institute of Marine Sciences and School of Fisheries, The Alaska Volcano Observatory, and the US Navy.

Stay with us for the “Summer of the Tiglax” as we report in on monitoring and research activities supported and facilitated by the Tiglax and crew!

 

Clams and Climate: Paleoenvironmental Reconstruction in the North Pacific Ocean

This blog is reposted from the Stable Isotopes in Zooarchaeology wordpress site. They are a Working Group of the International Council for Archaeozoology. Please cite their webpage in any use of this material.

Author: Christine Bassett | University of Alabama

The archaeological record reflects fluctuating marine conditions from the Aleutian Islands to the Northwest coast of North America during the Late Holocene (Wanner et al., 2008). Though not widely tested, recent research suggests that conditions may have cooled enough during the Late Holocene cold phase to allow sea ice to accumulate as far south as the Northern Pacific Ocean. My research is focused on establishing sclerochronological analysis of Saxidomus gigantea as a means of detecting differences in sea surface temperatures in the Northern Pacific Ocean. Sclerochronological and isotopic analysis of skeletal carbonates can provide a proxy for sea surface temperatures as well as the length of seasons during the recent geological record. My research will contribute to a larger project focusing on human and animal adaptation to climate change led by Fred Andrus (Univerisity of Alabama), Catherine West (Boston University), and Mike Etnier (Portland State University) by providing an additional proxy for reconstructing environmental conditions in the Late Holocene.

Figure 1. Cross-section of mature shell, age seven years, magnification 10x. The arrow denotes the distance between two annual winter growth lines (modified from Hallmann et al., 2009).

Figure 1. Cross-section of mature shell, age seven years, magnification 10x. The arrow denotes the distance between two annual winter growth lines (modified from Hallmann et al., 2009).

Sclerochronology is the study of the growth of invertebrate skeletons. I work exclusively with bivalves, whose distinct growth lines mark regular biologically and environmentally controlled growth intervals (Hallmann et al., 2009). Isotopic analysis of oxygen (δ18O) from growth lines can identify winter growth bands between successive growing seasons. Nadine Hallman and her colleagues (2009) examined the life history of S. giganteus and compared shell precipitation during the organism’s life with oxygen isotopic analysis. They determined that dark bands (Fig. 1) largely co-occurred with peaks in δ18O (Fig. 2). These dark bands mark the beginning and end of a season of growth and the interval between them represent the length of one growing season.

Figure 2. Upper: Shell oxygen isotope record (δ18O, black bars) compared with reconstructed temperature (Tδ18O, light grey curve) and sea surface temperature (SST, dark grey curve) data collected from http://www.cdc.noaa.gov. Lower: Daily growth increment width time series (n = number of increments per year. The blue bars represent the annual winter growth lines measured in (A). Positive δ18O values correspond with winter growth lines while negative δ18O were sampled from the portion of the shell between winter growth lines. Oxygen isotope data confirms annual winter growth lines. Specimen collected September, 9 2007 (modified from Hallmann et al., 2009).

Figure 2. Upper: Shell oxygen isotope record (δ18O, black bars) compared with reconstructed temperature (Tδ18O, light grey curve) and sea surface temperature (SST, dark grey curve) data collected from http://www.cdc.noaa.gov. Lower: Daily growth increment width time series (n = number of increments per year. The blue bars represent the annual winter growth lines measured in (A). Positive δ18O values correspond with winter growth lines while negative δ18O were sampled from the portion of the shell between winter growth lines. Oxygen isotope data confirms annual winter growth lines. Specimen collected September, 9 2007 (modified from Hallmann et al., 2009).

Measuring and comparing the lengths of seasonal shell growth from shells collected at higher latitudes with shells collected from slightly lower latitudes could provide a means of assessing changes in the length of growth seasons, possibly indicating differential sea surfaces temperatures between latitudes. Applying this method to ancient archaeological shells would allow me to test for changes in the length of growing season and by extension, the presence of cold conditions – and possibly sea ice – in the Northern Pacific Ocean during the Late Holocene.

Figure 3. Collection sites have not yet been determined. Potential site candidates are located along the Gulf of Alaska and include Unalaska (A) and Kodiak Islands (B), Alaska and Dundas Island, B.C. (C) (modified from NASA satellite image).

Figure 3. Collection sites have not yet been determined. Potential site candidates are located along the Gulf of Alaska and include Unalaska (A) and Kodiak Islands (B), Alaska and Dundas Island, B.C. (C) (modified from NASA satellite image).

Figure 4. Image of winter growth line in an acetate peel made from S. gigantea cross-section at 40X magnification (Personal image by Bassett, 2014).

Figure 4. Image of winter growth line in an acetate peel made from S. gigantea cross-section at 40X magnification (Personal image by Bassett, 2014).

To accomplish this, I plan to collect samples of Saxidomus gigantea from Alaska and Northern British Columbia (Fig. 3). I will analyze δ18O profiles across the organism’s second or third year of growth, the most ontogenetically reliable period of growth, to determine that winter growth bands correspond to peaks in δ18O so that later sclerochronological analysis can be performed. For sclerochronological analysis, I will prepare acetate peels (Fig. 4) so that I can then count lunar-daily growth lines between winter growth bands to quantitatively measure the length of the growing season. Assuming I can detect a difference in the length of the growing season between samples collected at different latitudes, I will apply the same method to ancient samples from the same regions. If the method tested here is successful, sclerochronological analysis of bivalves may be able to contribute to δ18O data interpretation and comparative studies with other organisms to provide a more comprehensive view of changes in SST through recent geological history. Understanding climate in the past contributes greatly to archaeological research that seeks to understand how human behavior, particularly the exploitation of floral and faunal resources, changes as components of the environment change.

REFERENCES

Hallmann, N., Burchell, M., Schone, B.R., Irvine, G.V., Maxwell, D., 2009, High-resolution sclerochronological analysis of the bivalve mollusk Saxidomus gigantea from Alaska and British Columbia: techniques for revealing environmental archives and archaeological seasonality. Journal of Archaeological Science, v. 36, pp. 2353-2364.

Wanner, H., Beer, J., Butikofer, J., Crowley, T.J., Cubasch, U., Fluckiger, J., Goosse, H., Grosjean, M., Joos, F., Kaplan, J.O., Kuttel, M., Muller, S.A., Prentice, C., Solomina, O., Stocker, T.F., Tarasov, P., Wagner, M., and Widmann, M., 2008, Mid- to Late Holocene climate change: an overview. Quaternary Science Reviews, v. 27, no. 19-20, pp. 1791-1828.

Volcanism and the Aleutian Islands

Authors: Dixie West: Kansas University; Mitsuru Okuno: Fukuoka University; Kirsten Nicolaysen: Whitman College; Breanyn MacInnes: Central Washington University; Virginia Hatfield: Kansas University

Volcanoes created the Aleutian Islands, and volcanic eruptions periodically impacted humans inhabiting the archipelago. Sizable geological events potentially disrupted food sources by killing fish; clogging spawning streams; and smothering ground nesting bird colonies, shellfish beds and sea mammal rookeries (Black 1981; Workman 1979). Volcanism also must have produced a powerful psychological effect on prehistoric Unangax^ (Black 1981).

West_Volcanoes

The August 2008 Kasatochi eruption in the central Aleutians is useful for understanding past geological impacts on humans and their natural world. The explosion covered the island with meters of ash, endangered USFWS biologists, killed thousands of chicks, and destroyed sea lion rookeries and the breeding grounds of over 100,000 ground nesting birds. Pyroclastic-flow deposits created a coastline approximately 400 m further into the sea, and initiated a small tsunami recorded by Atka, Adak and Amchitka tide gauges (USGS 2009)

Our research (e.g. Okuno et al. 2012; West et al. 2012) suggests that prehistoric peoples settled on north Adak Island nearly 7,000 years ago. Five major volcanic events are recorded on north Adak: the Main, Intermediate, Sandwich, YBO, and 40 Year ash occurrences (Black 1976). By dating plant materials charred by ash falls in prehistoric village sites and by comparing the relationship of these ashes with cultural layers, we can determine how human occupations were impacted by volcanic events. Site ADK-171, the earliest site on Adak, lies immediately above the Intermediate Ash that fell approximately 7200 years ago (Okuno et al. 2012). Cultural layers capping a poorly developed soil and Intermediate Ash indicate the volcanic explosion did not prevent humans from settling north Adak soon after the ash fell.

West_Stratigraphy

Recent North Pacific Rim research (e.g., Dumond 2011; Fitzhugh 2012) shows remarkable hunter-gatherer flexibility in the face of catastrophic geological events. Unangan resilience probably depended on multiple factors:

  • Intergenerational communication allowing all persons in any given group to recognize signs of an imminent disaster based on past experience of older individuals,
  • The capacity to pick up and move relatively quickly from impending danger,
  • An easily reproducible house architecture and technology if villages were destroyed and tools abandoned,
  • Possible communication with, and temporary aid from, Unangax^ living in nearby island groups, and
  • A remarkably consistent maritime ecosystem where adjacent islands possessed many, if not most, food resources and tool materials familiar to Unangan groups displaced by natural disasters.

The recently NSF funded research project “Collaborative Research: Geological Hazards, Climate Change, and Human/Ecosystems Resilience in the Islands of the Four Mountains” promises to add new information about the impacts of, and human reactions to, volcanic eruptions, tsunamis and other geological events in the eastern Aleutians. In 2014 Kirsten Nicolaysen, Breanyn MacInnes, Virginia Hatfield, and Dixie West will launch this three-year interdisciplinary research on Chuginadak and Carlisle Islands.

Black, Robert F. 1976.  Late Quaternary Glacial Events, Aleutian Islands, Alaska. In D. J. Easterbrook and V. Sibrava (eds.), Quaternary Glaciations in the Northern Hemisphere: IUGS-UNESCO International Geological Correlation Program, Project 73-1-24, 285-301. Bellingham, International Union of Quaternary Research.

Black, Lydia. 1981.Volcanism as a Factor in Human Ecology: The Aleutian Case. Ethnohistory 28(4), 313-333.

Dumond, Don. 2011. Archaeology on the Alaska Peninsula: The Northern Section. Fifty Years Onward. University of Oregon Anthropological Papers No. 78. Eugene.

Fitzhugh, Ben. 2012. Hazards, Impacts, and Resilience Among Hunter-Gatherers of the Kuril Islands, pp.19-42.  In J. Cooper and P. Sheets (eds.), Surviving Sudden Environmental Change: Answers from Archaeology. University Press of Colorado, Boulder.

Okuno, Mitsuru, Keiji Wada, Toshio Nakamura, Lyn Gualtieri, Brenn Sarata, Dixie West, and Masayuki Torii. 2012. Holocene Tephra Layers on the Northern Half of Adak Island in the West-Central Aleutian Islands, Alaska, pp. 59-74. In (D. West, V. Hafield, E. Wilmerding, C. Lefèvre, and L. Gualtieri, eds.), The People Before: the Geology, Paleoecology and Archaeology of Adak Island, Alaska. BAR International Series 2322, Oxford.

USGS. 2009. Small Volcano—Big Eruption  http://alaska.usgs.gov/science/kasatochi/2008_eruption.php

West, D., V. Hatfield, E. Wilmerding, C. Lefèvre, L. Gualtieri (eds.). 2012. The People Before: The Geology, Paleoecology and Archaeology of Adak Island, Alaska. British Archaeological Reports, 2322, Oxford.

Workman, William. 1979. The Significance of Volcanism in the Prehistory of Subarctic Northwest North America. In Volcanic Activity and Human Ecology. P. Sheets and D. Grayson, eds., pp. 339-371. Academic Press. New York.

Volcano Monitoring and Research in the Aleutian Islands by the Alaska Volcano Observatory

Author: Chris Waythomas, U.S. Geological Survey, Alaska Volcano Observatory (AVO), Anchorage, Alaska

The AVO is a partnership of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute (UAFGI), and the Alaska Division of Geological and Geophysical Surveys (ADGGS).

The Aleutian Islands are part of the Aleutian arc, one of the most active volcanic provinces on Earth, and they owe their existence to long-term volcanic activity. Volcanoes and their products dominate the landscape.  Volcanic ash from explosive eruptions in this area poses a substantial threat to the several hundred jet aircraft that fly over the region every day. To address the hazards associated with explosive ash producing eruptions, the Alaska Volcano Observatory (AVO) monitors and studies volcanoes in the Aleutian Islands and disseminates information regarding the status of unrest at active volcanoes in this area as well as other parts of Alaska.

Reporting Volcanic Unrest

AVO provides regular updates on volcanic unrest when a major change in the status of an Alaskan volcano occurs.  Information is distributed to state and federal agencies, municipalities, industry, and the general public through the USGS Volcano Notification System (VNS).  This information is also posted on the AVO web page (www.avo.alaska.edu) and a short synopsis is distributed via Twitter and Facebook.

Seismic Networks, Satellite Data, and Infrasound

An AVO seismic station on Little Sitkin volcano. This small hut contains all of the electronic equipment needed to relay seismic data from a seismometer buried nearby to a satellite uplink site on Amchitka Island.

An AVO seismic station on Little Sitkin volcano. This small hut contains all of the electronic equipment needed to relay seismic data from a seismometer buried nearby to a satellite uplink site on Amchitka Island.

AVO operates seismic networks on 32 historically active volcanoes and monitors all 52 historically active volcanoes in Alaska (including those in the Aleutian Islands) using remotely sensed data from satellites, observations from local observers and pilots, and other types of geophysical monitoring equipment. The seismic networks provide real-time information on earthquake activity that occurs at or beneath the volcano.  An increase in earthquake activity is often the best way to determine that a volcano may be progressing toward an eruption. The number and type of earthquakes provide important information used to give advance warning of an eruption. Once a volcano becomes restless, AVO provides information about potential hazards that may affect life and property. The principal hazard of concern to AVO is airborne volcanic ash and its impact on aircraft.  Additional hazards of concern include ash fallout, volcanic mudflows or lahars, and rapidly flowing mixtures of hot rock fragments, fluids, and gases known as pyroclastic flows.

AVO also does routine analyses of satellite data to identify thermal features indicative of magma at or near the surface. Usually, elevated levels of seismicity correspond with the appearance of thermal features at a restless volcano and the satellite information helps confirm that an eruption is occurring. Significant eruptive activity is typically explosive and results in the production of ash clouds, which can be detected and tracked in satellite data. Explosive eruptions usually generate pressure waves that travel through the air, which can be detected at locations hundreds of kilometers from the erupting volcano. Explosion signals detected by infrasound monitoring equipment are becoming an increasingly important tool for eruption detection at volcanoes that are not seismically monitored.

AVO in the Aleutian Islands

AVO scientists have not worked extensively in the Aleutian Islands. AVO did several weeks of helicopter-supported fieldwork in the western Aleutian Islands in 2003 and 2005, and preliminary geologic maps and hazard assessments were completed for Gareloi and Tanaga Volcanoes. Reconnaissance-level field visits were made to Little Sitkin and Semisopochnoi. In the late 1990’s AVO had brief field projects on Kanaga, Great Sitkin, and Unimak Islands, and also produced preliminary geologic maps and hazard assessments of Fisher caldera and Great Sitkin, Kanaga, Westdahl and Shishaldin volcanoes. AVO was very involved in the monitoring, analysis, and eruption response to the 2008 Kasatochi eruption, and continues to have a role in the study of ecosystem recovery and post-eruption landscape adjustment and erosion.

Current Operations

Funding for monitoring of Alaskan volcanoes, especially the hard-to-maintain volcanoes in the Aleutian Islands, has been in decline for several years.  AVO has deferred maintenance on geophysical monitoring networks at many previously well-monitored Alaskan volcanoes including those in the Aleutian Islands.  As a result, many seismic stations have gradually become inoperable or are functioning intermittently. As of mid-January 2014, only about half of AVO’s roughly 200 seismic stations were operating. Ground-based seismic monitoring is currently not operational or is functioning poorly at Gareloi, Shishaldin, Westdahl, and Semisopochnoi, which are considered high threat volcanoes. Ground-based seismic monitoring at Fisher caldera, Little Sitkin, and Isatnoski also is compromised or not functioning, although these volcanoes pose a lesser threat. To address these shortcomings in monitoring capability, AVO makes routine observations to detect unrest at all Alaskan volcanoes using satellite and regional infrasound data. It is not possible to forecast eruptions with these data, but eruption detection is possible, although delays in reporting unrest of tens of minutes to hours in some cases are likely.

The Future of AVO

Over the coming years, AVO will continue to pursue its volcano-monitoring mission, and will engage in geological field studies focused on hazards and past eruptive behavior where possible. Most of AVO’s resources will be directed to study and monitoring the highest threat volcanoes in the Aleutian arc, which are Mount Spurr, Redoubt, Augustine, Akutan, and Makushin volcanoes. Studies at other volcanoes will still take place, but this work will have lesser priority.

LittleSitkin_Hoffman* Header photo credit: Little Sitkin, Rat Islands. May 2009 by B. Hoffman (Hamline University)